Despite how well recognized of a subject this is becoming, schools still don't discuss it with their students in any classes. Even if the teacher or school doesn't think that any sort of sexuality that isn't heterosexual is wrong, they should at least let their students be informed so they can make their own opinions.
Why is this important?
Even if people are against any form of homosexuality, they shouldn't be able to ignore a large part of society. They don't have to agree with it, but they should be informed.